Electrical connector



July 21, 1953 w. s. WATTS Re. 23,688

ELECTRICAL CONNECTOR Original Filed Dec. 14, 1943 INVENTOR M14441 J%/77J.

F M M Q ATTORN Y5 Reiuued July 21,

ELECTRICAL CONNECTOR William S. Watts, Roselle, Ni J., assignor toAhcrait Marine Products, 1110., Elizabeth, N. 32, a corporation of NewJersey Original No. 2,410,321, dated October 29, .1946, Serial No.514,216, December 14, 1943. Application i'or reissue October 28, 1947,Serial No.

7 Claims. (Cl. 339-213) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italicsindicatcs the additions made by reissue.

1 I This invention relates to an electrical connector, and moreparticularly to a connector of the type which is adapted to be appliedand secured to electrical conductors by crimping of a ferrule onto aconductor received therein.

Connectors of the general type of which this invention is concerned,have been in commercial use prior to my present invention and aredisclosed, for example, in the application of Stephen S. Buchanan,Serial No. 421,408, filed December 3, 1941, issued as Patent No.2,379,567 on July 3, 1945, and Serial No 474,935, filed February 6,1943; and in the application of Carlson and Freedom, Serial No. 459,624,filed September 25, 1942. In the terminals as illustrated in these priorcopending applications a ferrule is formed of a size adapted to receivethe bare conductor,

e. g., the end of the stranded wire of an insulated I cable, and overthis is applied a metal sleeve extended beyond the open end of theferrule so as to receive and support an insulated portion of theinsulated cable. As commonly applied this extended sleeve has beencrimpcd onto the insulation at the same time that the ferrule is crimpedonto the bare portion of the conductor. This, for example. is disclosedand a suitable tool therefor is shown and described in an application ofVernon E. Carlson, Serial No. 455,033, filed August 17, 1942.

In many cases it is desirable that the exposed portions of the terminalof the ferrule should be non-conducting, either so as to avoid dangerousor disagreeable shock to persons making adjustments or repairs while theterminals are carrying relatively high voltages or to prevent accidentalcontact with nearby terminals or other conducting parts. Although it hasbeen common practice prior to my invention, with other types ofterminals, to provide insulated sleeves, it has not heretofore beenconsidered feasible to use an insulated sleeve on a terminal which is tobe crimped upon a wire. I have now discovered that, if an insulatingsleeve is made of a tough stiifly flexible, more or less rubbery plasticof about the same order of thickness as the metal of the ferrule, e. g.from about a tenth up to about three or four times the thickness of themetal, depending upon the toughness and. other properties of theplastic, the resulting insulated ferrule may be used in substantiallythe same manner and crlmpcd with the same types of tools as those madeentirely of metal. e. ts, as described in the atom-mentioned oopendingapplication. More over, I have found that rubbery plastics or the typewhich may be subjected. to severe deformation and which would recoveronly slowly after such deformation may be used with advantage, accordingto my invention; and thus, to the extent that such plastics may bedamaged during the crimping operation, the damage is repaired by thegradual recovery of the plastic after its release from the crimpingdies. This is of particular advantage when it is desired to mold orcrimp the sleeve onto the insulation at the same time that the ferruleis crimped onto the wire. Plastic, materials adapted to be thus formedonto the insulation tend to cut or extrude to some extent, irom underthe crimping die in the areas where the ferrule is crimped onto thewire, and thus may expose at certain points the conducting metal of theferrule. The gradual recovery of the plastic will cause it to creep backover such exposed surfaces and thus give a satisfactory insulation-ofthe entire ferrule.

In order to prevent a similar recovery of the portion of the sleevewhich serves as the insulaticn support, the material of which it is mademay be chosen with respect to the surface material of the wire so thatthe two adhere strongly when pressed together; or. if this is notconvenient, a surface coating on the interior of the sleeve may serve asan adhesive for this purpose.

Although I am giving below and showing in the accompanying drawing,preferred cmbodimcnts of my invention and suggesting variousmodifications thereof and alternatives, it should be understood thatthese are not intended to be exhaustive or limiting of "the invention,but on the contrary, are given. for purposes of illustration andexplanation, in order that others skilled in the art may fullyunderstand the invention, the principles thereof, and the manner ofapplication for practical use, and may thereby be snabled to embody andadaptthe invention in numerous forms and with numerous modifications.each as may be best adapted to the provisions of a particular use.

In the accompanying drawing:

Figure l is a View in longitm cal section oi a terminal embodying myinvention, ready for application to an insulated wire;

Figure is a porsp tive View on a reduced shown in Figure 1, applied andcrilnpcd onto a wire;

Figure 3 a. view ill longitudh'ial section, sir-oi Karly to that inFigure 1, bodiment of my invc Figure a is diagrumr View in sideclovation illustrzrtlm; one method of making the terminal shown. inFigure cases 3' 4 As shown in Figure 1, a metal portion of the ofinsulating material, a metal sleeve II is used terminal it may besubstantially identical with of substantially the same form as thatdisclosed that described in the copending application menin theapplication of Freedom and Carlson above tioned above. For example, itmaybemade from referred to. Between this and the ferrule II, sheet metalhaving a flat tongue portion ii and 5 howevenwhen the two are assembled,is inserted a ferrule portion 12 made by rolling into cylina layer ofinsulation Its, whereby the outer sleeve drical form, with the buttingedges lateral or ll, although of conducting material, actually istensions integral with the tongue portion .l I. not in conductingrelation to the circuit. This This metal portion can advantageously bemade terminal may be applied and crimped onto the of dead soft annealedcopper whereby it may be wire in exactly the same manner as indicated incrlmped onto the wire and coined by the crimp- Figure '2. During thecrimping operation, the,

ing tool so as to form asubstantially solid mass outer sleeve it tendsto relieve somewhat the sewith the inserted wire and have a permanentVere strain imposed on the plastic insulating maunion therewith,substantially without springterial and to oppose any tendency of theplastic to back 15 flow laterally out from under the crimping die.

Over the ferrule i2 is the insulating sleeve II In Figure 4. I haveshown diagrammatically which tightly engages the ferrule. Depending onemethod of making the terminals of Figure 3. upon the material used, thismay be a press ilt, In this case a flat sheet of plastic is placed or,advantageously, if as indicated above, the maover a drawing die It inwhich the sleeve II is terial is one whichmay besubiected to severe fited and suitably held. The ferrule II is then deformation and will tendto recover gradually Dressed down into the sleeve II (with or withoutits original size and form, the sleeve may be preliminary drawingOperations) to perform the stretched to a larger diameter, fitted overthe eeve "a. The ferrule i2 carries with it the ferrule, and thenallowed to shrink onto it. This M81310! which s formed and drawn ysubject matter is more particularly described and the ie t and p essedsuflici tiv to a low the claimed in the copending application ofFrank'Ja wo parts to enter tog r. I1 the Sheet lib is Sowa, Serial No.560,785, filed October as, 1944. e nyl plas su h a is described a v Thisprocess can be facilitated by stretching at the tendency of the materialto recover gradually room temperature and warming the sleeve to a w e 0!i n th the stre hed matehigher temperature to accelerate its recovery.fli l radually w farther into the B1306 Likewise, if it is desirable tohold a supply of betwen the sleeve ll and-the ferrule i! to the thestretched ferrules for some time, they may full extent permissible by edi erence between beicnul d t delay t recovery their diameters. This canbe hastened as indi- I have found an advantageous material for this byWarming the terminals a te avpurposeto be a vinyl chloride vinyl acetateco- 8 n flBBc b fld a r00!!! temperature even polymer, slightlyplasticized with any of the usual llighlily chilled. I plasticizers, e.g., tricresyl phosphate. Such ma- A the assembly p fl d ore terial iscommercially available in the form of 1" his process of shrinking iscomplete, the extruded tubes [and may, for example. be obend which isstretched over the end of the fertainedunder the tradename Irviiite"from the 40 rule if may be punched out or this may be left IrvingtonVarnish Works, Irvington, New Jersey] in Place and punctured when thestranded wire on the interior of the extendedend of the is inserted.sleeve II, I have shown a coating of adhesive ll. Although the terminalshown in Figure 3 has This may be any known relatively stable adhesivethe advantage that in its finished appearance it compatible with thematerials used for the sleeve is substantially identical .with theterminals alit and the materials commonly used for surfacready in wi ecomm rcial use. the terminal of ing insulated wire. I have found thepressure- 8 1! 1 is t e u t e adv a e that the sensitive adhesives, madefrom degraded rubber stiflly flexible plastic sleeve allows some yieldsuch as are commonly used in adhesive tapes, are with flex nfi of theinsulated cable, so that sharp satisfactory for this purpose. 5D bendingis avoided: and, due to its flexibility and In the use of this terminalthe end of an insuits slow recovery, it also tends to damp vibrationslated wire is first stripped to expose the central in the wire and thusto protect the actual conductor of twisted stranded wire. This is thencrimped connection in the ferrule from this deinserted in the end of thesleeve II, the central structive influence. stranded conductor extendingon into the ferrule 5 I claim:

If, while the insulation itself extends only into 1. An electricalconnector of the type intended thesleeve l3 abutting against the ends ofthe to be crimped onto a wire and including a soft ferrule, The assemblymay then be crimped. in metal ferruleand a normally risid tube of tougha tool such as that shown in the copending apand stiiily -iiexibleinsulating plastic tightly smplication of Veron E. Carlson abovereferred to; so bracing said ferrule and covering the outer surwhereuponthe ferrule 12 and the surrounding face thereof, said tube having aresistance to cold portions of the sleeve it are flattened and coinedplastic flow not significantly less than that of the onto the wire,whereas the outer end of the sleeve metal of said ferrule, whereby saidtube can II is crimped and formed so as tightly to embrace transmitsumcient crimping pressure to the ferthe'insulation of the wire and tobe cemented as rule from a crimp tool to crimp the ferrule thereto bythe adhesive ll. Whereas the sleeve against a conductor by plastic flowin the metal I! will tend to recover so as to repair any breaks them!without crack ng the tube or otherwise whichimay possibly have occurredduring the interfering with its mechanical and ectrical rsevere crimpingof ferrule II, the adhesive ll fectiveness.

tendsto hold the outer portion of the sleeve in 2. An electricalconnector as defined in claim its pressed and deformed condition asshown, 1 wherein the plastic of said tube is of the type counteractingthe tendency of the sleeve to rehaving plastic memory, which tendsgradually to cover its wider form. recover its original form aftersevere deforma- In' Figure 3, I have shown an alternative struction.ture, wherein instead of using a simple sleeve ll 76. 8 An electricalconnector as defined in claim 1 wherein said tube extends substantiallybeyond the end of said ferrule whereby to receive and support aninsulated portion of an insulated wire and has a coating of non-dryingpressure-sensitive adhesive on the interior of said extended portion ofthe tube, whereby said extension may be secured to the insulated wire.

4. An electrical connector as defined in claim 1 wherein a thin metalsleeve surrounds said plastic tube.

5. A connector for use in a crimped joint comprising a cylindricallyshaped metal body portion having an open end for receiving a conductortherein, an insulating cover thereon, said insulating cover having thephysical properties of permitting an indenting tool to be appliedeasternally to the insulation and causing the metal body underneath tobe indented in the form of a recess to a conductor therein, and ofsubstantially retaining the shape of the recess in the insulation afterthe tool has been withdrawn.

6. A connector for use in a crimped joint comprising a cylindricallyshaped metal body portion having an open end for receiving'a conductortherein, an insulating cover thereon, said insulating cover having thephysical properties of toughness, flexibility and plasticity, whereby totransmit from an externally applied indenting tool to said metal bodyportion beneath it a localized force, suflicient to indent said bodyonto 1 a conductor within said body in an area beneath said indentingtool, and of substantially retaining the shape of the recess produced bysuch indenting tool after the tool has been withdrawn.

7. A connector for use in a crimped joint comprising a cylindricallyshaped metal body portion having an open end for receiving a conductortherein; an insulating cover thereon, said insulating cover having thephysical properties of permitting an indenting tool to be applied ea:-ternally to the insulation and causing the metal body underneath to beindented in the form of a recess to a conductor therein and of initiallyretaining the approximate shape of the recess in the insulation alterthe tool has been withdrawn but having a tendency to return, at least tosome extent, to the shape it had prior to indenting.

WILLIAM S. WA'I'IS.

References Cited in the file of this patent or the minimal patent UNITEDSTATES PATENTS Number Name Date 2,035,911 Mucher Mar. 31, 1936 2,148,392Ransome Feb. 21, 1939 2,173,668 Smith Sept. 10, 1939 2,297,336 WhiteSept. 29, 1942 2,338,524 McCabe Jan. 4, 1944 FOREIGN PATENTS NumberCountry Date 847,814 France July 10, 1939

